TECHNICAL BACKGROUND
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The present invention relates to a work vehicle for carrying out
agricultural work and related work.
BACKGROUND ART
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One type of work vehicles is composed of a pair of left-hand and
right-hand traveling sections, each of a crawler type, a vehicle body frame
member interposed between the pair of the left-hand and right-hand
traveling sections with a motor section, an operation section and a
transmission section disposed thereon in this order from the front portion to
the rear portion of the vehicle body. The traveling sections are operatively
coupled with the motor section through the transmission section, and the
transmission section combines a rotational velocity of a straight-traveling
power transmission system and a rotational velocity of a cornering power
transmission system. The combined rotational velocity then drives
independently and separately each of the left-hand and right-hand
traveling sections.
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Each of the left-hand and right-hand traveling sections is further
composed of a longitudinal frame member extending in the
forward-rearward direction, drive and follower wheels mounted on a front
end portion and a rear end portion of the longitudinal frame member, and a
crawler wound about the drive and follower wheels.
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The motor section disposed at the front portion of the vehicle body,
and the operation section is located behind the motor section. The
operation section is provided with a steering lever, and a steering link
mechanism system is interposed between the steering lever and the
transmission section to conduct the steering operation of the vehicle body.
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The work vehicle of the above-mentioned conventional type,
however, has the drawbacks as will be described hereinafter.
- (1) The conventional work vehicle of the above type presents the
disadvantage that it cannot thrust its vehicle body into a soft ground in
which the earth is piled up about to the height on level with the lowest
ground level.
- (2) The conventional work vehicle further suffers from the problem
that a forward visible field in front of the vehicle body cannot be ensured for
the operator handling the steering lever while seated on the operator' s
seat in the operation section due to the fact that the motor section is
disposed in front of the steering lever mounted in the operation section.
- (3) Although the conventional work vehicle of the above type can
steer the vehicle body by means of the steering lever, however, this
operation with the steering lever presents the disadvantage that it is unlikely
for the operator to secure a steering feeling for adjusting a fine cornering
velocity of the vehicle body.
- (4) The conventional work vehicle has the problem that the steering
link mechanism system restricts the freedom of layouts so that a compact
disposition cannot be achieved.
- (5) For the conventional work vehicle with the traveling sections
each of the crawler type having the structure as described above, a link
mechanism system for shifting the cornering directions is separately
provided in order to ensure operability and safety because the cornering
steering direction becomes opposite to the cornering operation direction of
the vehicle body at the time of forward traveling and rearward traveling.
This work vehicle, however, may cause a so-called breakdown at the link
connection portion so that the operation cannot be achieved with a high
accuracy and a good operability cannot be ensured.
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DISCLOSURE OF THE INVENTION
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Therefore, the present invention provides a work vehicle having a
pair of left-hand and right-hand traveling sections each of a crawler type,
a frame member of a vehicle body interposed between the pair of the
left-hand and right-hand traveling sections with an operation section, a
motor section and a transmission section disposed on the vehicle body
frame member; wherein the traveling section comprises a longitudinal
frame member extending in a longitudinal direction; front and rear follower
wheels mounted on front and rear end portions of the longitudinal frame
member, respectively; a drive wheel interposed between and above the
front and rear follower wheels and operatively coupled with the motor
section through the transmission section; and a crawler in a triangular form,
when looked from the side, wound about the drive wheel and the front and
rear follower wheels; and wherein the operation section is provided with a
steering wheel disposed at a forefront portion of the vehicle body.
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Further, the present invention has the features as will be described
hereinafter.
- (1) The vehicle body is provided with a front PTO shaft at a front
portion thereof and the vehicle body is provided with a rear PTO shaft at a
rear portion thereof; and the front PTO shaft and the rear PTO shaft are
operatively coupled with the motor section through the transmission
section.
- (2) The work vehicle comprising a pair of left-hand and right-hand
traveling sections each of a crawler type, a frame member of a vehicle
body interposed between the pair of the left-hand and right-hand traveling
sections with an operation section, a motor section and a transmission
section disposed on the vehicle body frame member; having the pair of the
left-hand and right-hand traveling sections coupled operatively with the
motor section through the transmission section; and driving the pair of the
left-hand and right-hand traveling sections independently and separately
by means of a combined rotational velocity obtained by combining a
rotational velocity of a forward-traveling power transmission system with a
rotational velocity of a cornering power transmission system; in which the
operation section is provided with a steering wheel for steering the pair of
the left-hand and right-hand traveling sections and the steering wheel is
operatively coupled with a cornering non-stage shift system for
accelerating and decelerating the rotational velocity of the cornering power
transmission system to associate an operation of the steering wheel for
rotating in the left direction and the right direction with an operation of the
cornering non-stage shift system for normal and reverse rotation.
- (3) The steering wheel is operatively coupled with a steering link
mechanism system through a steering wheel support shaft and the steering
link mechanism system is operatively coupled with a trunnion arm member
of the cornering non-stage shift system.
- (4) A trunnion arm member of a forward non-stage shift system is
operatively coupled with a shift lever for shifting a forward traveling
operation or a rearward traveling operation or shifting a speed of the vehicle
body to associate an operation of the shift lever for shifting a forward
traveling operation or a rearward traveling operation or shifting a speed of
the vehicle body with the operation of the forward non-stage shift system
for normal or reverse rotation.
- (5) The vehicle body is provided with a floor section at a front
portion thereof and a front portion of the floor section is formed inclining
forward in an upward way.
- (6) The steering link mechanism system is formed in a compact
manner and disposed directly under the front portion of the floor section
formed inclining forward in an upward way.
- (7) The steering link mechanism system is provided with a rotational
direction shift mechanism system for shifting a normal rotational direction
or a reverse rotational direction of an output shaft of the cornering
non-stage shift system; and the rotational direction shift mechanism
system is operatively coupled with the shift lever to associate an operation
of the shift lever for the forward shift or the rearward shift with an operation
of the output shaft of the cornering non-stage shift system for shifting the
normal rotational direction or the reverse rotational direction by the
rotational direction shift mechanism system.
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BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
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- Fig. 1 is a side view showing a work vehicle according to the
present invention.
- Fig. 2 is a plan view showing a transmission section of the work
vehicle.
- Fig. 3 is a side view in section showing a link box.
- Fig. 4 is a plan view in section showing the link box.
- Fig. 5 is a sectional view when view along line I-I of Fig. 3.
- Fig. 6 is a sectional view when view along line II-II of Fig. 3.
- Fig. 7 is a sectional view when view along line III-III of Fig. 3.
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BEST MODES FOR CARRYING OUT THE INVENTION
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The work vehicle according to the present invention has a basic
structure comprising a pair of left-hand and right-hand traveling sections
each of a crawler type and a vehicle body frame interposed between the
pair of the left-hand and right-hand traveling sections and having an
operation section, a motor section and a transmission section disposed on
the frame member of the vehicle body. The motor section is operatively
coupled with the left-hand and right-hand traveling sections via the
transmission section. A rotational velocity of a straight-traveling power
transmission system is combined with a rotational velocity of a cornering
power transmission system at the transmission section, and the combined
rotational velocity drives the left-hand and right-hand traveling sections
separately and independently.
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As the featuring structure of the work vehicle, each of the left-hand
and right-hand traveling sections is composed of a longitudinal frame
member extending in the forward-rearward direction, front and rear follower
wheels mounted respectively on the respectively front and rear end portions
of the longitudinal frame member, a drive wheel disposed between and
above the front and rear follower wheels and coupled operatively with the
motor section through the transmission section, and a crawler in a
triangular form, when looked from the side, wound among the drive wheel
and the front and rear follower wheels.
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Further, the vehicle body is provided with the front PTO shaft at the
front portion thereof, and it is provided with the rear PTO shaft at the rear
portion thereof, in which the front and rear PTO shafts are operatively
coupled with the motor section through the transmission section.
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Moreover, the operation section is provided with a steering wheel for
steering the left-hand and right-hand sections at the forefront portion of
the vehicle body, in which the steering wheel is operatively coupled with a
steering link mechanism system through a steering wheel support shaft to
operatively couple the steering link mechanism system with a trunnion arm
member of a cornering non-stage shift system for accelerating or
decelerating a rotational velocity of the cornering non-stage shift system
and to associate an operation of the steering wheel for left-hand rotation
and right-hand rotation with an operation of the cornering non-stage shift
system for normal rotation or reverse rotation.
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Furthermore, a trunnion arm member of a forward-traveling
non-stage shift system for accelerating or decelerating a rotational velocity
of a forward-traveling power transmission system is operatively coupled
with a shift lever for shifting the forward traveling or a rearward traveling and
changing the velocity of the vehicle to associate the operation of the shift
lever for shifting the forward traveling or rearward traveling and changing
the velocity of the vehicle with the operation of the forward-traveling
non-stage shift system for normal rotation or reverse rotation.
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With the structure as described above, the steering link mechanism
system is built in a link box in the form of a flat box, when looked from the
side, and disposed under the floor section disposed at the front portion of
the vehicle body. Further, the steering link mechanism system is provided
with a rotational direction shift mechanism system for shifting the normal
and reverse rotational direction of an output shaft of the cornering
non-stage shift system, which is operatively coupled with the shift lever to
associate the forward and rearward traveling operation of the shift lever with
the operation of the cornering non-stage shift system for shifting the
normal and reverse rotational direction.
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The present invention will be described in more detail by way of
working examples with reference to the accompanying drawings.
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In Fig. 1, the work vehicle according to the present invention is
shown as a work vehicle A to which a tilling machine B as a work machine
is connected at its rear end portion via a lifting link mechanism system C.
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As specifically shown in Fig. 2, the work vehicle A is composed of a
pair of left-hand and right-hand traveling sections 1 and 1, each of a
crawler type, and a vehicle body frame member 2 interposed between the
traveling sections 1 and 1. Further, the frame member 2 is provided with an
operation section 3 thereon, and a motor section 5 is disposed on the
frame member 2 behind an operator' s seat 4 of the operation section 3.
A transmission section 6 is disposed under the operator' s seat 4, which is
operatively coupled with the motor section 5. Moreover, the transmission
section 6 is operatively coupled with drive wheels 13 and 13 of each of the
traveling sections 1 and 1 via traveling transmission mechanism systems 7
and 7, respectively.
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A front PTO shaft 8 is disposed projecting forward at the front
portion of the vehicle body, and a rear PTO shaft 9 is disposed projecting
rearward at the rear portion thereof. The front and rear PTO shafts 8 and 9
are operatively coupled with the transmission section 6.
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The traveling section 1 is composed of a longitudinal frame
member 10 extending in the forward-rearward direction, a front follower
wheel 11 and a rear follower wheel 12, both being mounted on the
respectively front and rear end portions of the longitudinal frame member
10, a drive wheel 13 interposed between and disposed above the front and
rear follower wheels 11 and 12, and a crawler 14 in a triangular shape,
when looked from the side, wound among the drive wheel 13 and the front
and rear follower wheels 11 and 12. In Fig. 2, reference numeral 16 stands
for an idler fork, reference numeral 17 for a bolt for adjusting the forward or
rearward movement of the idler fork, reference numeral 18 for a rolling
wheel, and reference numeral 19 for a crawler-slippage preventive
member.
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The vehicle body frame member 2 is composed of a front latitudinal
frame member 20 and a rear latitudinal frame member 22, both being
interposed between the pair of the left-hand and right-hand longitudinal
frame members 10 and 10, respectively, and disposed in a predetermined
spaced relationship apart therefrom, a front support member 23 disposed
rising upward from the front latitudinal frame member 20, a rear support
member 24 disposed rising upward from the rear latitudinal frame member
22, and a guard frame member 25 in the form of a square-shaped ring,
when looked from the top, interposed between the front and rear support
members 23 and 24, respectively.
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As shown in Figs. 1 to 3, the operation section 3 is provided with a
floor section 26 at the front portion of the guard frame member 25, which
in turn is composed of a front portion 26a extending rising in a forward
direction. Further, a space S is formed at the position directly under the
front portion 26a of the floor section 26, in which a steering link
mechanism system 31 is disposed.
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On the front portion 26a of the floor section 26, a steering column
27 is disposed standing upright at the front portion 26a thereof, and a
steering wheel support shaft 28 extending upwardly is inserted into the
steering column 27. Further, a steering wheel 29 is disposed at the
forefront portion of the vehicle body by mounting the steering wheel 29 on
the upper end portion of the steering wheel support shaft 28.
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In the space S formed directly under the front portion 26a of the
floor section 26, a steering link mechanism system 31 built in a link box 30
is operatively coupled at the bottom end portion of the steering wheel
support shaft 28. Further, a trunnion arm member 76a of a cornering
non-stage shift system 76, as will be described in more detail later, is
operatively coupled with the steering link mechanism system 31 to
associate an operation of the steering wheel 29 for left-hand and
right-hand rotations with the operation of the cornering non-stage shift
system 76 for normal and reverse rotations.
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A steering link mechanism system-protective member 33 is
disposed directly in front of the link box 30 hanging at the front end portion
of the guard frame member 25 in order to cover and protect the front
portion of the steering link mechanism system 31.
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Further, the steering link mechanism system 31 is disposed above a
virtual line L1 at an angle set between the virtual line L1 and the ground
surface G, in which ┌ ┌ the virtual line L1 is the line tangent to a portion of
the crawler 14 passing under the bottom end of the steering link
mechanism system-protective member 33 and wound about the front
follower wheel 11.
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With the structure as described above, the steering link mechanism
system-protective member 33 can ensure a sure protection of the steering
link mechanism system 31 from bumping into irregular surfaces on the
ground G and consequently from damages, breakage and so on due to.
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The operator' s seat 4 is disposed behind the steering wheel 29,
and a shift lever 32 is disposed at the left-hand side position of the
operator' s seat 4, which can shift the forward-rearward movements and
speeds of the vehicle.
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The shift lever 32 is operatively coupled with a trunnion arm member
77a of a straight-traveling non-stage shift system 77 that can accelerate or
decelerate the rotational velocity of a forward-traveling power transmission
system as will be described in more detail later in order to associate the
operations of the shift lever 32 for shifting forward and rearward movement
and speeds of the vehicle body with the operations of the straight-traveling
non-stage shift system 77 for shifting normal and reverse rotations and
accelerating or decelerating velocities of the vehicle body.
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The steering link mechanism system 31 built in the link box 30 is
further provided with a rotational-direction shift mechanism system 34 for
shifting the normal and reverse rotational directions of an output shaft (not
shown) of the cornering non-stage shift system 76, which in turn is
operatively coupled with the shift lever 32 so as to associate the operations
of the shift lever 32 for shifting the forward-rearward movements and the
velocities of the vehicle with the operations of the output shaft of the
cornering non-stage shift system 76 for shifting the normal and reverse
rotational direction by means of the rotational-direction shift mechanism
system 34.
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As specifically shown in Figs. 2 to 4, the link box 30 extends in the
forward-rearward direction, when looked from the top, and is formed in a
flat box shape, when looked from the side. The link box 30 is mounted
from the bottom on the guard frame member 25 through a stay 35.
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At the front portion of the link box 30, an association shaft 36 with
its axis directed upwardly is supported rotatably about the axis thereof, and
an upper edge portion of the association shaft 36 is disposed projecting
upwardly from a projection hole 41 formed in a ceiling portion 30a of the
link box 30 and operatively coupled coaxially with a lower edge portion of
the steering wheel support shaft 28. In the drawings, reference numeral 37
stands for a support shaft casing member.
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Moreover, the association shaft 36 is provided with an output gear
38 at the top portion thereof and with a rotation-regulating recipient piece
member 39 at the bottom portion thereof, the rotation-regulating recipient
piece member 39 being disposed projecting rearward in a state intersecting
at a generally right angle. On the other hand, the rotation-regulating
recipient piece member 39 rotates in association with the rotational
operations of the steering wheel 29 from the neutral position in the rearward
projecting state to allow the tip portion thereof to come into engagement
with a rotation-regulating piece member 40 from one of the left-hand and
right-hand directions, the rotation-regulating piece member 40 being
disposed projecting upwardly from the front end portion of the bottom part
30b of the link box 30. Moreover, this can regulate each of the left-hand
and right-hand rotations of the steering wheel 29 at the angle within a
range smaller than 180 degree.
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As shown in Figs. 3 to 7, the steering link mechanism system 31
built in the link box 30 is composed of a swinging member 45 mounted at
the middle portion of the ceiling part 30a of the link box 30 so as to swing
to the left and to the right, a laterally movable member 46 interposed
between a left side wall 30c and a right side wall 30d of the link box 30 and
mounted at the position directly under the laterally movable member 46 so
as to move in the left-hand and right-hand directions, an engagement pin
47 interposed between the swinging member 45 and the laterally movable
member 46 so as to engage with the two members, and an association
arm member 48 with the tip portion thereof engaged with the laterally
movable member 46 and with the base end portion thereof mounted to the
bottom part 30b of the link box 30 so as to swing to the left and to the
right.
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The swinging member 45 is composed of a main body 45a formed
extending in the forward and rearward directions, and a swinging member
support shaft 45b disposed projecting upwardly from the central top portion
of the main body 45a toward the axial line thereof. The swinging member
support shaft 45b is supported on the ceiling part 30a of the link box 30.
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The main body 45a of the swinging member 45 is formed in such a
manner that the front edge portion thereof is shaped in an arc form and a
partial gear 45c is provided on the arc-shaped face. Further, the swinging
member 45a is provided at the bottom face thereof with an engageable
groove 45d at the swinging member side, which extends in the forward and
rearward directions.
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The partial gear 45c is in mesh with an output gear 38 formed at
the upper portion of the association shaft 36 and the swinging member 45
is disposed so as to swing about the swinging member support shaft 45b
in association with the association shaft 36.
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On the other hand, the laterally movable member 46 is composed
of a cylindrical main body 46a thereof with the axial line thereof directed to
the left-hand and right-hand directions, and an engagement piece
member 46b linked to the top face of the cylindrical main body 46a thereof
at a state intersecting at a normal angle. The main body 46a of the laterally
movable member 46 is slidably mounted on a slide support shaft 49
interposed between the left-hand and right- hand side walls 30c and 30d of
the link box 30, respectively.
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The engagement piece member 46b is shaped in a box form with
the open top extending in the forward and rearward directions, and the
inside of the engagement piece member 46b forms an engageable groove
46c at the laterally movable member side. Reference symbol 46d stands
for a depressed portion for a temporary stop at the neutral position, which
is formed at a central portion of the engageable groove 46c at the laterally
movable member side and on a virtual axial line of the swinging member
support shaft 45b.
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The engagement pin 47 is formed with the axial line thereof directed
upwardly and forms a depressed portion 47a for accommodating a
temporarily stopping ball, which is open at the bottom portion thereof. The
depressed portion 47a accommodates a temporarily stopping ball 47b and
a pressing spring 47c urging elastically the temporarily stopping ball 47b in
a downwardly pressed state to engage the temporarily stopping ball 47b
with the depressed portion 46d and to temporarily stop the engagement pin
47 at the neutral position.
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Further, the engagement pin 47 is slidably engaged at the bottom
end portion thereof with the engageable groove 46c of the engagement
piece member 46b at the laterally movable member side, and it is slidably
engaged at the top portion thereof with the engageable groove 45d of the
swinging member' s main body 45a at the swinging member side.
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The association arm 48 at the base end portion is mounted on the
top portion of a shaft 50 with the axial line thereof inserted upwardly into
the bottom part 30b of the link box 30. On the other hand, the association
arm 48 at the tip portion is engaged with a branched engagement piece
member 46e formed at the central bottom portion of the main body 46a of
the movable member.
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Further, an operational arm member 51 at the base end portion
extending toward the left-hand side is mounted on the bottom portion of
the shaft 50 projecting outwardly from the bottom part 30b of the link box
30, and the operational arm member 51 at the tip portion thereof is
operatively coupled with the trunnion arm member 76a of the cornering
non-stage shift system 76 via a cornering HST association mechanism
system 52.
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The rotational-direction shift mechanism system 34 for shifting the
normal and reverse rotational direction of the output shaft of the cornering
non-stage shift system 76 is interposed between the shift lever 32 and the
engagement pin 47.
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More specifically, the bottom portion of the shift lever 32 is
mounted through a boss portion 54 on a lever support shaft 53 with its axial
line directed in the left-hand and right-hand directions, and a shift arm
member 55 is disposed on a boss portion 54 projecting upwardly in the
forward direction.
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A rear wall 30e of the link box 30 is provided with a rod insertion
hole 56, and a rod 57 extending in the forward-rearward direction is
inserted into the rod insertion hole 56 slidably in the forward-rearward
direction. Between the rear end portion of the rod 57 and the tip portion of
the shift arm member 55 is interposed a shift operation-association
mechanism system 58. Further, the front end portion of the rod 57 is
supported by and connected to the rear end portion of an engagement
pin-connecting piece member 59 through a connecting pin 60 with its axial
line directed upwardly, and the engagement pin 47 is connected to the
front end portion of the engagement pin-connecting piece member 59.
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Further, the boss portion 54 is provided with a straight-traveling
HST operation arm member 61 projecting rearward and downward, and a
straight-traveling HST association mechanism system 62 is interposed
between the straight-traveling HST operation arm member 61 and the
trunnion arm member 77a of the straight-traveling non-stage shift system
77.
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When the shift lever 32 is held in the manner as described above at
the neutral position at which it stands upright, as shown in Fig. 3, the
temporarily stopping ball 47b of the engagement pin 47 is engaged with
the depressed portion 46d for use in temporarily stopping the engagement
pin at the neutral position and the engagement pin 47 is held in such a
state that it is temporarily stopped at the neutral position.
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In this state, even if the steering wheel 29 would be rotated in either
of the left-hand or right-hand direction, the laterally movable member 46
cannot move in the lateral direction due to the fact that the swinging
member support shaft 45b and the engagement pin 47 are positioned on
the identical axial line, although the swinging member 45 could be swung
by the partial gear 45c about the swinging member support shaft 45b in
either of the left-hand or right-hand direction.
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Therefore, the association arm member 48 engaged with the
laterally movable member 46 at the tip portion does not work so that the
cornering non-stage shift system 76 is held at the neutral position.
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Then, as shown in Fig. 5, when the shift lever 32 is rotated forward
to the forward-traveling shift status, the rotational-direction shift
mechanism system 34 is allowed to slide forward as a whole to slidably
transfer the engagement pin 47 to the position of the front edge portion
within the engageable groove 46c at the laterally movable member side and
the engageable groove 45d at the swinging member side, and the trunnion
arm member 77a of the straight-traveling non-stage shift system 77 is
shifted to the forward-traveling side through the straight-traveling HST
association mechanism system 62.
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For example, as shown in Fig. 4, when the steering wheel 29 is
rotated to the left-hand side in the state as described above, the swinging
member 45 is swung to the right-hand side about the swinging member
support shaft 45b as indicated by the solid line and then the laterally
movable member 46 is moved laterally to the right-hand side through the
engagement pin 47.
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As a consequence, the association arm member 48 engaged with
the laterally movable member 46 at the tip portion thereof is allowed to
pivot to the right-hand side and the operational arm member 51 coupled
operatively with the association arm member 48 via the shaft 50 pivots
rearward from the neutral position (as indicated by the dotted line) directed
toward the right-hand side to turn the trunnion arm member 76a of the
cornering non-stage shift system 76 in the left-hand direction through the
cornering HST association mechanism system 52 and to turn the vehicle
body as a whole to the left-hand side from the forward- and
straight-traveling status.
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Further, when the steering wheel 29 is steered to turn to the
right-hand side in the state as described above, each of the swinging
member 45, the laterally movable member 46, the association arm
member 48, the operational arm member 51, the cornering HST
association mechanism system 52 and the trunnion arm member 76a of
the cornering non-stage shift system 76 is operated in the opposite
direction to turn the vehicle body to the right from the forward- and
straight-traveling status.
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Then, when the shift lever 32 is steered to pivot rearward to the
rearward-traveling status, the rotational-direction shift mechanism system
34 is allowed to slide as a whole in the rearward direction to slidably
transfer the engagement pin 47 to the position of the rear edge portion
within the engageable groove 46c at the laterally movable member side and
the engageable groove 45d at the swinging member side, and the trunnion
arm member 77a of the straight-traveling non-stage shift system 77 is
shifted to the rearward traveling side through the straight-traveling HST
association mechanism system 62.
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In this state, for example, as shown in Fig. 4, when the steering
wheel 29 is steered to turn to the left-hand side, the swinging member 45
is swung to the right-hand side about the swinging member support shaft
45b and as a consequence the laterally movable member 46 is allowed to
move laterally to the left-hand side by means of the engagement pin 47 as
indicated by the two-dotted line.
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As a consequence, the association arm member 48 engaged with
the laterally movable member 46 at the tip portion thereof pivots to the
left-hand side and the operational arm member 51 coupled operatively with
the association arm member 48 through the shaft 50 then pivots forward
from the neutral position (as indicated by the one-dotted line) directed to
the right-hand side to turn the trunnion arm member 76a of the cornering
non-stage shift system 76 to the right via the cornering HST association
mechanism system 52 and then shift the output shaft to the reverse
rotational direction and turn the vehicle body to the left and to the
rearward-traveling status from the rearward- and straight-traveling status.
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Therefore, although the work vehicle according to the present
invention is provided with the traveling sections 1 and 1, each of the crawler
type, the vehicle body can be turned in the same direction, even when is
turned in the rearward- and straight-traveling status, as when it is turned in
the forward- and straight-traveling status. This can provide the work vehicle
according to the present invention with a favorable level of operability and
safety.
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Further, when the steering wheel 29 pivots to the right in the state
as stated above, each of the swinging member 45, the laterally movable
member 46, the association arm member 48, the operational arm member
51, the cornering HST association mechanism system 52 and the trunnion
arm member 76a of the cornering non-stage shift system 76 is operated in
the opposite direction to turn the vehicle body rearward to the right-hand
side from the rearward- and straight-traveling status.
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In the embodiments as described above, the steering link
mechanism system 31 requiring a high accuracy of arrangement of the link
connection portion is incorporated in the link box 30 so that the operation
can be carried out with a high degree of accuracy without causing a
so-called irregularity and operational performance can be ensured to a
favorable extent by incorporating the steering link mechanism system 31
pre-adjusted in the link box 30 with a high degree of accuracy.
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Moreover, the link box 30 can reduce the number of assembly work
steps to a great extent by forming it in a compact structure, thereby
reducing costs of preparation and rendering it easy to arrange for a
small-sized work vehicle having a small space, thereby rendering it readily
feasible to apply versatile kinds of work vehicles.
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The motor section 5 is composed of an engine E as well as a
radiator, an air cleaner (although not shown), and so on, disposed in the
vicinity of the engine E.
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As shown in Fig. 2, the transmission section 6 is composed of a
transmission casing member 70, a lateral casing member 71 extending
through the transmission casing member 70 in the left-hand and
right-hand direction, and a longitudinal casing member 72 extending
rearward and linked operatively to the right-hand side end portion of the
latitudinal casing member 71 at the front end portion thereof.
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Further, the lateral casing member 71 is provided with an input shaft
73, and the engine E is provided with an output shaft 74, in which a
universal joint 75 is interposed between the input shaft 73 and the output
shaft 74.
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Moreover, the rearward extending casing member 72 is provided
with a cornering power transmission system and a straight-traveling power
transmission system (although not shown), and a combined rotational
velocity is created by combining the power of the cornering power
transmission system with the power of the straight-traveling power
transmission system by means of a planetary gear mechanism system (not
shown) mounted in the rearward extending casing member 72. The
combined rotational velocity can drive each of the,left-hand and right-hand
traveling sections 1 and 1 by means of a traveling transmission mechanism
systems 7 and 7, respectively, as will be described hereinafter.
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In addition, a cornering non-stage shift system 76 of a electrostatic
type at the right-hand side wall thereof, which forms part of the cornering
power transmission system, and a straight-traveling non-stage shift system
77 of an electrostatic type, which forms part of the straight-traveling power
transmission system, are associatively provided on the right-hand side wall
of the rearward extending casing member 72 , and the rotational velocity of
the cornering power transmission system can be accelerated or decelerated
by the cornering non-stage shift system 76.
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Furthermore, the straight-traveling non-stage shift system 77 can
be arranged so as to accelerate or decelerate the rotational velocity of the
straight-traveling power transmission system in substantially the same
manner as described above. Thus, the cornering non-stage shift system 76
and the straight-traveling non-stage shift system 77 can be subjected to
operation for accelerating or decelerating the rotational velocity by means
of the steering wheel 29 and the shift lever 32.
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Each of the traveling transmission mechanism systems 7 and 7 is
provided with a drive shaft casing member 78 of a cylindrical form,
extending outwardly to the left-hand or right-hand side from the
respectively left-hand or right-hand rear side wall of the rearward extending
casing member 72, and a front gear casing member 79 is associatively
disposed with the outer side end wall of the drive shaft casing member 78.
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On the other hand, the rear portion of each of the left-hand and
right-hand longitudinal frame members 10 and 10 is provided with each of
left-hand and right-hand drive wheel support shaft casing members 80 and
80, each of a cylindrical form, with the axial lines thereof directed in the
left-hand and right-hand direction, respectively, through a casing stay
member 81. In the inner side end portion of each of the drive wheel support
shafts 80 and 80, there is associatively disposed a rear gear casing
member 82. Each of the drive wheel support shaft casing members 80 and
80 is operatively coupled with a rear gear casing member 82 at the inner
side end portion thereof. Further, a transmission shaft 83 is interposed
between the front gear casing member 79 and the rear gear casing
member 82 disposed facing in the forward-rearward opposite directions,
and a drive wheel support shaft 84 is inserted into each drive wheel support
shaft casing member 80. Moreover, the drive wheel support shaft 84 is
operatively coupled with the rear gear casing member 82 at the inner side
end portion thereof, and each of the drive wheels 13 and 13 is mounted at
the outer side end portion of each of the drive wheel support shafts 84 and
84.
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With the arrangement of the work vehicle in the manner as
described above, the combined rotational velocity formed by combining the
rotational velocity of the cornering power transmission system with the
rotational velocity of the straight-traveling power transmission system in the
rearward extending casing member 72 is transmitted through drive shafts
(not shown) inserted into the drive shaft casing members 78 and 78 to the
front gear casing members 79 and 79, respectively, then followed by
transmitting the combined rotational velocity through the transmission
shafts 83 and 83 and then the rear gear casing members 82 and 82 to the
drive wheel support shafts 84 and 84, respectively. The combined rotational
velocity is then transmitted to the drive wheels 13 and 13 and then to the
crawlers 14 and 14, respectively.
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The front PTO shaft 8 is disposed projecting forward from the front
decelerating casing member 85 via the latitudinal casing member 71 of the
transmission section 6 so that the power can be transmitted therefrom to a
snow removal machine (although not shown) or other machines connected
to the front portion of the work vehicle A.
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On the other hand, the rear PTO shaft 9 is disposed projecting
rearward from the right-hand side portion of a rear decelerating casing
member 86 disposed at the rear portion of the frame member 2 of the
vehicle body, and a PTO transmission shaft 87 is interposed between the
left-hand side portion of the rear decelerating casing member 86 and the
left-hand side portion of the longitudinal casing member 71.
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In the embodiments as described above, the rear PTO shaft 9 is
operatively coupled with an input shaft 91 through a tilting
apparatus-transmitting shaft 92, the input shaft 91 being disposed
projecting forward from a tilting casing member 90 of the tilting machine B.
INDUSTRIAL APPLICABILITY
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The present invention can achieve the effects as will be described
hereinafter.
- (1) The work vehicle according to the present invention has the
frame member of the vehicle body thereof interposed between a pair of the
left-hand and right-hand traveling sections each of a crawler type, with the
operation section, the motor section and the transmission section disposed
on the frame member of the vehicle body. Each of the traveling sections is
composed of a longitudinal frame member extending in the
forward-rearward direction, front and rear follower wheels mounted on the
respective front and rear end portions of each traveling section, the drive
wheel interposed between the front and rear follower wheels and disposed
over them as well as operatively coupled with the motor section through the
transmission section, and the crawler in the triangular form, when looked
from the side, wound between the drive wheel and the front and rear
follower wheels. The operation section is provided with the steering wheel
disposed in the forefront portion of the vehicle body.
As the front portion of the crawler for the traveling section of the
work vehicle wound is shaped in a triangular form at an acute angle, when
looked from the side, the work vehicle can move smoothly even on a soft
ground, particularly on a ground piled up on level with the approximately
lowest ground level. Therefore, this structure of the crawler can improve
traveling performance and work performance.8*-Further, the steering wheel of the operation section is disposed at
the forefront portion of the vehicle body so that a good forward visible field
can be ensured for the operator performing the steering operation with the
steering wheel while being seated on the operator' s seat in the operation
section. Therefore, this structure of the vehicle body can also provide a
high level of traveling performance and work performance and improve
safety to a great extent.Moreover, the operator can also operate the steering wheel while
walking on the ground in front of or along the vehicle body. Therefore, for
example, the operator may otherwise feel the fear in operating the work
vehicle on an inclining ground such as vineyards or the like while seated on
the operator' s seat in the operation section. Even in this case, however,
the work vehicle according to the present invention can help the operator in
removing the fear in conducting work on an inclining ground and can readily
operate the vehicle body by means of the steering wheel while walking on
the ground in front of or along the vehicle body.
- (2) The vehicle body of the work vehicle is provided with the front
PTO shaft at the front portion thereof and with the rear PTO shaft at the
rear portion thereof. Further, the front PTO shaft is operatively coupled with
the rear PTO shaft through the motor section and the transmission section.
Therefore, the power can be taken from the front PTO shaft when a
working machine or the like is coupled with the front portion of the vehicle
body in accordance with working conditions and so on. On the other hand,
the power can be taken from the rear PTO shaft when a working machine
or the like is coupled with the rear portion of the vehicle body in order to
adapt to work for versatile uses.
- (3) The work vehicle according to the present invention is composed
of a pair of the left-hand and right-hand traveling sections each of the
crawler type and the frame member of the vehicle body interposed between
the left-hand and right-hand traveling sections, with the operation section,
the motor section and the transmission section disposed on the frame
member. The operation section is operatively coupled with the traveling
sections via the transmission section that can combine the rotational
velocity of the straight-traveling power transmission system with the
rotational velocity of the cornering power transmission system to yield a
combined rotational velocity. The combined rotational velocity can drive the
left-hand and right-hand traveling sections independently and separately.
Further, the operation section is provided with the steering wheel for
steering the traveling sections, and the steering wheel is operatively coupled
with the cornering non-stage shift system for accelerating or decelerating
the rotational velocity of the cornering power transmission system to
associate the operations of the steering wheel for the left-hand and
right-hand rotations with the operations of the cornering non-stage shift
system for the normal and reverse rotations.
The cornering non-stage shift system can be rotated to the normal
or reverse direction in proportion to a steered amount of the left-hand or
right-hand rotation of the steering wheel in the manner as described above.
Further, it can accelerate or decelerate the rotational velocity of the
cornering power transmission system. Therefore, the operator operating the
rotation of the steering wheel can readily obtain a feeling of operation for
adjusting a minute cornering speed of the vehicle body. This can also
assist in improving operability.
- (4) For the work vehicle according to the present invention, the
steering link mechanism system is operatively coupled with the steering
wheel via the steering wheel support shaft and it is further coupled
operatively with the trunnion arm member of the cornering non-stage shift
system.
This structure can operatively couple the steering wheel with the
cornering non-stage shift system readily and certainly, thereby improving
operating performance and workability.
- (5) For the work vehicle according to the present invention, the shift
lever is operatively coupled with the trunnion arm member of the
straight-traveling non-stage shift system for accelerating or decelerating
the rotational velocity of the straight-traveling power transmission system,
whereby the forward-rearward shift operations of the shift lever can be
associated with the operation for the normal or reverse rotation by means
of the straight-traveling non-stage shift system.
This structure enables an easy operation of the steering wheel for
performing the forward-rearward shifts and a non-stage shift operation
between the forward range and the rearward range bridging the neutral
position of the shift lever.Therefore, the work vehicle according to the present invention can
achieve operating efficiency to a remarkable extent because the forward-and
rearward-traveling speeds of the vehicle body can be adjusted at a
non stage in accordance with working conditions and so on.
- (6) For the work vehicle according to the present invention, the
operation section has the floor section at the front portion of the vehicle
body, which is formed inclining upwardly in a forward direction.
The upwardly inclining floor section at the front portion of the
operation section allows the operator to place the feet thereon in a safe
manner even upon traveling on a ground inclining downward. Therefore, the
operator can achieve a safe operation without feeling a fear even while
operating the vehicle on a downward inclining ground.
- (7) The work vehicle according to the present invention is provided
with the steering link mechanism system formed in a compact structure
and disposed directly under the front portion of the floor section inclining
upwardly in a forward direction.
As the compact-structured steering link mechanism system is
disposed directly under the front portion of the floor section in the manner
as described above, it can be prevented from damages and breakage upon
impact on irregular surfaces of the ground while traveling. Further, a space
on the floor section at and around the feet of the operator can be made
considerably wide open so that the freedom of the space at and around the
feet of the operator can be ensured to a great extent. As a consequence,
seating comfortableness and operability of the vehicle body can be
improved to a great extent. In other words, the work vehicle according to the present invention
allows the steering link mechanism system coupled operatively with the
steering wheel via the steering wheel support shaft to be disposed in a
compact manner directly under the front portion of the floor section, so
that the surroundings around the steering wheel support shaft can be
rendered slimmer and consequently the space of the floor section at and
around the feet of the operator can be rendered wide. Therefore, the
freedom of the space on the floor section at and around the feet of the
operator can be ensured to a great extent. Moreover, seating
comfortableness and operability of the vehicle body can be improved
greatly.
- (8) For the work vehicle according to the present invention, the
steering link mechanism system is provided with the rotational-direction
shift mechanism system for shifting the normal and reverse rotational
directions of the output shaft of the cornering non-stage shift system, and
the rotational-direction shift mechanism system is operatively coupled with
the shift lever to associate the forward- and rearward-traveling shift
operations of the shift lever with the operations for shifting the normal and
reverse rotational directions of the output shaft of the cornering non-stage
shift system by means of the rotational-direction shift mechanism system.
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The operating performance of the rotational-direction shift
mechanism system can be ensured, like the steering link mechanism
system, in the manner as described above. Further, the rotational-direction
shift mechanism system can prevent an occurrence of an error operation by
bringing the cornering direction at the time of rearward traveling into
agreement with the direction of the cornering operation of the vehicle body,
even upon operating the shift lever for the rearward-traveling status. As a
result, the work vehicle according to the present invention can greatly
ensure operability and safety.